Google Pixel 8 Pro 5G GUKD8 Replacement Battery 3.89V 5050mAh

Google Pixel 8 Pro 5G — 3.89V Li-Polymer Replacement Battery (GUKD8)

This 3.89V, 5050mAh Li-Polymer cell replaces the original power unit in the Google Pixel 8 Pro 5G (model GC3VE). It matches OEM part numbers GUKD8 and G949-00704-01. Rated at 19.64Wh, it fits the Pixel 8 Pro and Pixel 8 Pro 5G variants that share the same chassis and battery bay dimensions.

• Pixel 8 Pro platform fit: The Pixel 8 Pro and Pixel 8 Pro 5G share an identical battery bay, connector pinout, and BMS handshake protocol — which is why a single cell covers both variants. The replacement uses the same physical dimensions (94.40 × 51.80 × 5.80mm) and voltage rail as the factory unit, so the charge IC sees no mismatch on boot.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on a Pixel 8 Pro unit. The BMS accepted the handshake without throwing a battery health warning, and the charge IC ramped to fast-charge current normally after the first complete cycle.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. The fuel gauge IC is still calibrated to the old cell's discharge curve. Running one full cycle at standard current lets the coulomb counter map the new cell before high-current fast charging pushes into an uncalibrated state.

Why the Pixel 8 Pro reports wrong battery percentage after a cell swap

The Pixel 8 Pro uses a coulomb counter and a learned discharge curve stored against the old cell. When you install a new cell, that stored curve no longer matches the actual voltage-to-capacity relationship of the replacement. The OS reads state-of-charge from the fuel gauge IC, which is still referencing old data. Until the IC runs at least one full uninterrupted discharge-charge cycle, percentage readings will drift — most noticeably in the 15–40% range where voltage slope is steepest. After one calibration cycle, the reported figure tracks actual capacity accurately.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff issue, not a defective cell. Under peak modem load or sustained screen brightness, the Pixel 8 Pro draws enough current to pull the cell voltage below the BMS cutoff threshold — even when the fuel gauge still shows charge remaining. The BMS sees terminal voltage drop below approximately 3.2V under load and trips a protective shutdown before the OS can respond. To confirm, charge to 100%, let the phone idle, and check voltage under active 5G use with a battery stats app. If voltage sags below 3.3V under load, the cell is behaving normally and the fuel gauge will self-correct after one full calibration cycle.